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gotwind
Forum Admin
United Kingdom
762 Posts |
 Posted - 03/04/2008 : 20:24:32
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I'm quite happy to offer help to this group of people doing good work in Africa.
Initialy I was just going to offer free advice on how to choose the correct solar products,batteries e.t.c it's surprising how little some people know about what seems very obvious to me.
Flexible solar panels were decided upon for longevity (vibration issues mounted on a bike) - 4 times the price per watt though 
I priced the job and it was about 300 U.K pounds, (approx $600) and decided to pay for it myself for a bit of gotwind publicity.
http://www.gotwind.org/cycle_of_life_2008.htm
I must have made close on that amount of money selling the wind generator plans now and again, so the funding is actually all being re-cycled for the good of others.
I'm not sure if I would like to be sat on a bike saddle for 5000 miles however - ouch...
Ben.
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gotwind
Forum Admin
United Kingdom
762 Posts |
Posted - 04/04/2008 : 21:35:21
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Thanks Ghurd for the reply on fieldlines - I'm Cross pollinating between forums now :)
Ghurds response
Wow Ben, That's a Big Job!
Some of the new gear takes USB. And at least some 12V to USB chargers are switchers. That's gotta help.
I think I'm going solar, to 11 Ni-Cds, to a 12V to USB switcher for about the same thing. (cell phone, GPS, etc)
My wife is a bike nut.
Anyway. Here is what I intend to use.
(Email for a UK supplier)
And they are not designed to be opened for a quick look. :-/
At least they are cheap!
http://www.otherpower.com/images/scimages/2050/USBswitcher.jpg
G-
The Futures Green - Getwind of it. |
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gotwind
Forum Admin
United Kingdom
762 Posts |
Posted - 04/04/2008 : 21:42:32
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I am noticing that the mini USB connection is becoming the standard for the latest mobile phones at least.
This allows for the re-use of the old, usualy disguarded 'wall wart' chargers we seem to see in every new mobile phone deal packages.
It has to be a good thing to standardise these things.
I wonder how the various voltages and constant current requirments are met between phone manufacturers, Nokia, Motorolla e.t.c ?
Out of interest Ghurd, what are 'switchers'?
Thanks
Ben. |
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ghurd
Junior Member
USA
274 Posts |
Posted - 04/04/2008 : 23:59:38
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BEN!
I only saw this while trying to post a photo link thing as a photo.
I'm not as smart as some people think.
Cross pollinating doesn't bother me.
boy- this got long winded.
Yes. Standardization is great. Imagine if that $40 cell phone charger for the car worked with this phone. And the next phone!
That is never the case here in the US.
Cell phone and constant current is a myth, by what I have seen. Maybe because they all limit the current to less than 500ma max. The 5V USB supply limits it. Lots of variables in that mess.
I never had a problem with a 5V/500ma supply input being fed 5V peak at 100ma max. The phone seems to take the input into account.
Readers should only do that if understanding it could smoke their phones.
"Switchers" are super-great.
Like 1W in = 1W out?
But it never works for 12V in and 5V out, because they use linear 7805s?
(1A in = 1A out) Meaning it loses 7W.
A 'switcher' is 1W in and 1W out. Almost.
Meaning 1W out (IE: 5V at 200ma=1W) is equal to 1W in (IE: 12V at 83ma).
Meaning 83ma out of a 12V battery supplies a 5V load with 200ma. That is good.
If the battery is 12V, and the 5V supply is a 7805, then the wasted power is 60%.
If the battery is 12V, and the supply is a switcher, then the waste is much smaller. Maybe 15%?
The same system could do the same work with about 1/2 the solar power!
Your PV system just got 50% smaller and with 50% less battery.
Gotta love that!
I am leaning to 11 nicds at 13.8V. 12V PVs. "12V" to USB switcher.
That is for a Garmin 305 (with ALL extra stuff), a cell phone, and an LED torch.
Meaning (for me) a $2 do-hicky saves me $50 in PVs and batteries. And she doesn't have to carry it for 1,000 miles.
The photo you show above must be a switcher. A linear would melt the platic at 0.5A.
G-
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